[sdiy] resampling wav files

Richie Burnett rburnett at richieburnett.co.uk
Thu Apr 19 19:54:14 CEST 2018


Are these wavetables?

You can upsample then downsample but there is a simpler way.

You can do the resampling operation in one step using polyphase sinc interpolation to calculate 256 new points of the original continuous time waveform that would be "off grid" from the 600 sample points that you currently have. (You might need to band-limited the original wavetable first though if it contains energy at frequencies above what will be the new nyquist frequency, otherwise this energy will alias and then get frozen into your new 256 sample wavetable).

A good place to ask about this stuff is the music DSP mailing list. Or if you look through the archives people like RBJ or Nigel Redmon have posted about resampling many times before. 

-Richie, 

Sent from my Xperia SP on O2

---- Tim Ressel wrote ----

>Hi,
>
>Looks like there's some DSP in my future. I need to resample wave files 
>to get them from 600 samples down to 256 samples. Unless there is a 
>groovy toll out there that can do that, I gotta write an app for it. As 
>far as I can tell I need to interpolate 32x and then decimate 75x, with 
>all the attendant filters that these processes need. I know just enough 
>DSP to be dangerous.
>
>Thoughts?
>
>-- 
>--Tim Ressel
>Circuit Abbey
>timr at circuitabbey.com
>
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